Cut the potatoes into chunks, and boil in water to cover or until
tender, but not mushy.

Meanwhile wash and trim the kale or cabbage, discarding any
tough stems.
Chop it and steam for 5-10 minutes, or until tender.
Cool it and gently squeeze out the water.
At the same time, in a lightly oiled skillet, steam-fry the leeks
until softened.

Drain the potatoes well and mash with a potato masher.
Beat in the soymilk, then the cooked kale or cabbage and leeks.
Add salt and pepper to taste.